Filtering system

ABSTRACT

A filtering system for water treatment including a head member having fluid inlet and outlet ports, a bracket member adapted to be secured to stationary support means, the head member being secured to the bracket member, a disposable filter cartridge closed at one end and being equipped at its other end with a closure member, the closure member having inlet and outlet passages formed therein to communicate with the interior of said filter cartridge, the closure member portion of the filter cartridge being insertable into the head member, its inlet and outlet passages formed so as to communicate with the inlet and outlet ports in the head member, the closure member being adapted for easy insertion into and withdrawal from the head member.

.Iadd.This is a continuation of copending application Ser. No.07/355,636 filed on May 22, 1989 now abandoned, which, in turn, is areissue of U.S. Ser. No. 837,197 filed Mar. 7, 1986, now U.S. Pat. No.4,725,354. .Iaddend.

BACKGROUND OF THE INVENTION

This invention relates to a filtering system and more particularly to asystem in which a disposable filter cartridge can be inserted into andremoved from a head member which is permanently mounted in a fluidconduit.

SUMMARY OF THE INVENTION

An object of the invention is to provide in a water treatment system aconvenient economical filter assembly wherein a disposable filtercartridge can easily be installed in the line by hand without the use ofcumbersome extra tools.

A further object of the invention is to provide a filter assemblyincluding an integral disposable filter unit constructed and arranged insuch manner that line pressure will not be effective to dislodge thefilter unit from the head member.

Other objects and advantages of the invention will become more apparentfrom the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view in elevation of a filter assembly embodyingthe invention herein in an assembled position;

FIG. 2 is a sectional view in elevation of another filter assemblyembodying the invention but using a different filter means in the filtercartridge;

FIG. 3 is a sectional view in elevation of the closure member of typefitted in the open end of a pressure vessel as shown in FIGS. 1 and 2;

FIG. 3A is a partial sectional view of the head member of FIGS. 1 and 2illustrating an alternative venting construction;

FIG. 4 is a sectional view in elevation of a filter assembly embodyingthe invention in an assembled position and showing the filter cartridgein a hanging position as distinguished from the inverted position ofFIGS. 1 and 2;

FIG. 5 is a sectional view in elevation of a filter assembly similar tothat shown in FIG. 4 embodying the invention but using a differentfilter means in the filter cartridge;

FIG. 5A is a plan view taken along line 5A--5A of FIG. 5;

FIG. 6 is a sectional view in elevation of a filter assembly similar tothat shown in FIG. 4 embodying the invention but using a filter meanssimilar to that shown in FIG. 2;

FIG. 7 is a sectional view in elevation of the closure member of thetype fitted in the open end of a pressure vessel as shown in FIGS. 4, 5,and 6;

FIG. 8 is a plan view of the filter assembly of FIG. 6;

FIG. 9 is a plan view of the bracket member as shown in FIG. 8; and

FIG. 10 is a bottom plan view of the head member taken along line 10--10of FIG. 4.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to the drawings wherein like reference characters refer tolike parts the filter assembly 10 as shown in FIG. 1 includes a bracketmember 12 for supporting a head member and a filter cartridge, a headmember 14 secured to the bracket member and a filter cartridge 16 whichis inserted into and supported in the head member.

The bracket member 12 includes a generally laterally extendingplate-like portion 20 with a substantially vertically extending integralportion 22 which may be removably attached to a supporting structure bysuitable fastening means.

A circular opening 24 is formed in the laterally extending portion 20for receiving therethrough the end of the filter cartridge.

The head member 14, preferably of a molded plastic, is a cylindricalcup-like structure which may be formed with a pair of oppositelydisposed flanges 26a and 26b (not shown) by which it is secured to thebracket member. In the embodiment of both FIGS. 1 and 2 the head member14 is shown with the opening to the head member facing upwardly so thata filter cartridge is inserted in an upside down position downwardlythrough opening 24 in the bracket member into the head member 14. FIGS.4, 5, and 6 by contrast show the filter cartridge supported in a hangingor upright position similar to that shown in our copending U.S. patentapplication Ser. No. 799,948 on a Filtering System filed Nov. 18, 1985.

A bore 28 is formed in the head member 14 for receiving the lower end offilter cartridge 16 therein. A pair of ports 30 and 32, one an inlet andthe other an outlet, are formed in the cylindrical wall 34 of the headmember. In the embodiment shown in FIG. 1, 30 is the inlet port, and 32is the outlet port although these may be reversed depending on the typeof filter arrangement within the pressure vessel, such as the differentfilter arrangement in FIG. 2 as will be subsequently described inconnection with the description of FIG. 2. Appropriate connections madeto these ports 30 and 32 is what incorporates the filter assembly into afluid conduit which provides the water to the unit or device whichultimately uses the filtered or treated water.

At its lower end as seen in FIG. 1 the head member 14 is formed with aninternally directed axially extending tubular alignment projection 36offset from the bore axis which is intended to be received by a matingbore in the closure member of the filter cartridge. A vent hole 38 isformed in the end of the tubular alignment projection to vent air or anyfluid that may have collected in the bore 28 for one reason or anothersuch, for example, as during filter cartridge replacement activity.

Instead of the integral projection 36 formed on the end wall of the headmember a pin 36a may be positioned in an opening formed in the end wallof the head member as shown in FIG. 3A. The pin would be formed with avent opening 38a and be received in the bore 60.

The filter cartridge 16 of FIG. 1 includes a pressure vessel 40, aclosure member 42, and a filter media 46. The filter cartridge isdesigned as an integral disposable unit which may be easily insertedinto and removed from the head member 14 without the use of specialtools.

The pressure vessel 40 which may be of metal or plastic is closed at itsupper end as shown in FIGS. 1 and 2, and the closure member 42 issealingly permanently fitted into the open end of the pressure vessel byappropriate means.

The closure member 42 of FIGS. 1, 2, and 3 which preferably is made of aplastic material includes an annular base portion 48, which is theportion secured into the open end of the pressure vessel, and issealingly fitted into the open end with a seal means 49. The closuremember includes an elongated generally cylindrical portion 50 formedintegrally with the base portion. The cylindrical portion 50 is insertedinto the head member 14 in the assembly.

A pair of substantially axially extending fluid inlet and outletpassages 52 and 54 are formed in the elongated cylindrical portion 50 ofthe closure member and as shown in FIG. 1, 52 is the inlet passage and54 is the outlet passage. A third port 56 is formed in the cylindricalsidewall of the cylindrical portion 50 in communication with passage 52.Another fluid port 58 is formed in the cylindrical sidewall of thecylindrical portion 50 in communication with passage 54 and in axiallyspaced relation with fluid port 56. In the assembly of FIG. 1 fluid port56 communicates with inlet port 30 formed in head member 14 and fluidport 58 communicates with outlet port 32 formed in head member 14. Abore 60 is formed in the lower end of closure member 42 and aspreviously noted is adapted to receive alignment projection 36 of thehead member 14 to thus align in the assembly the inlet and outlet ports56 and 58 of the closure member 42 with the inlet and outlet ports 30and 32 of the head member 14. The vent hole 38 in the alignmentprojection 36 is effective to vent from the head member 14 any fluidthat may collect in the head member.

O-ring seals 62, 64, and 66 are disposed on the outer cylindricalsurface of the cylindrical portion 50 of the closure member. The O-ringseal 64 is disposed at a point on the closure member so that inlet fluidentering inlet port 30 will be sealed off from outlet fluid exitingthrough outlet port 32. O-ring seal 66 is effective to prevent theleakage of inlet fluid to the outside through vent hole 38. O-ring seal62 is effective to prevent the leakage of filtered fluid to the outside.

With the type of construction as illustrated the fluid pressure aroundthe cylindrical portion of the closure member 42 at both the inlet andoutlet is acting in radial planes between the O-ring seals. There is,therefore, no axial pressure as in a piston which might tend to forcedisengagement between the closure member 42 and the head member 14.

The filter cartridge 16 as shown in FIG. 1 includes an inlet tube 68which is connected to inlet passage 52 of the closure member in asuitable manner. The inlet tube 68 extends to near the top of thepressure vessel 40 and carries at its upper end a tubular screenstrainer 70. In this particular embodiment the pressure vessel containsa filter media 46 which may substantially fill up the entire pressurevessel. The filter media preferably is a granular activated carbon.Influent liquid entering the inlet 30 moves through inlet tube 68 andscreen strainer 70, into and through the filter media 46 and out of thepressure vessel via outlet passage 54 and fluid outlet 58.

Insertion and removal of the integral disposable filter unit is donewith ease without the necessity of extra tools such as wrenches, etc. Inthis essentially inverted position gravity is effective to hold thefilter cartridge in its normal operating position in the head member 14,the weight of the filter cartridge being sufficient to maintain thefilter cartridge and head member in an operable relationship. Thecooperating alignment means on the head member and the closure member,namely the alignment pin 34 and mating bore 60, make it easy topositively align the inlet and outlet ports in the head member andclosure member.

The embodiment shown in FIG. 2 differs from the FIG. 1 embodiment inthat a different filter means is used in the pressure vessel. Thisdifference in filter means then makes it necessary to reverse the flowof liquid through the head member and closure member. In FIG. 2 acylindrical filter unit 74 is used. It is formed with a central passage76 closed at its upper end. The passage 76 is aligned with passage 52 inthe closure member 42. The unit 74 may be a string wound filter or aspun bonded unit. In this case the influent water enters through port32, moves through passage 54 as indicated by the arrows, into thepressure vessel 40, passes radially inwardly through the filter unit 74to the center thereof into control passage 76 and out through passage 52and outlet port 30.

The embodiments of FIGS. 4, 5, and 6 illustrate filter assemblieswherein the filter cartridges are essentially in an upright or hangingposition as distinguished from the inverted position illustrated inFIGS. 1 and 2. In the embodiments of FIGS. 4, 5, and 6 the closuremembers which are sealingly secured into the open ends of the pressurevessels are substantially the same as the closure member 42 shown inFIGS. 1, 2, and 3. Since the filter cartridges of FIGS. 4, 5, and 6,however, are in a hanging position securing means is provided to preventthe filter cartridge from becoming dislodged by gravity from itsposition in the head member. This securing means includes bayonet lugsformed on the closure member, which in the assembly coact with the headmember and the bracket member to secure the filter cartridge in placeand prevent dislodgement due to gravity. This bayonet lug means issubstantially as described in our copending application Ser. No. 798,948referred to above. The head member, of course, is mounted on a bracketmember in an inverted position from that shown in FIGS. 1 and 2.

The filter assembly 110 shown in FIG. 4 includes a bracket member 112for supporting a head member and a filter cartridge, a head member 114secured to the bracket member 112 and a filter cartridge 116 which isinserted into and supported in the head member.

The bracket member 112 includes a generally laterally extendingplate-like portion 120 with a substantially vertically extendingintegral portion 122 which may be removably attached to a supportingstructure by suitable fastening means. A circular opening 124 is formedin the laterally extending portion 120 for receiving therethrough theupper end of the filter cartridge. A pair of oppositely disposed bayonetopenings 125a and 125b are connected to the opening 124. The width A ofopening 125a is narrower than width B of opening 125b for reasons to besubsequently explained.

The head member 114 is substantially similar to the head member 14 shownin FIGS. 1 and 2 but there are these differences. The lower end of bore128 is enlarged at its lower end in the form of a counterbore 129 forthe purpose of coacting with bayonet lugs on the closure member of thefilter cartridge 116 as further described below.

In addition as distinguished from the head member of FIGS. 1 and 2 noalignment pin means is associated with the upper end wall 133 of headmember 114 because alignment of the inlet and outlet ports of theclosure member of the filter cartridge with the inlet and outlet portsformed in the head member is achieved by other means. A vent hole 138 isformed in the upper end wall 133 of the head member 114 to vent air andmoisture from the head member when the filter cartridge is inserted intothe head member.

The filter cartridge 116 of FIG. 4 includes a pressure vessel 40, aclosure member 142, a filter septum 143 and a filter media 46 which isthe same as the filter media shown in FIG. 1. The filter cartridge 116,just as the filter cartridge 16 of FIGS. 1 and 2, is designed to be anintegral disposable unit which may be easily inserted into the headmember 114 and removed therefrom by hand without the use of specialtools. The same is true for the filter cartridge of FIGS. 5 and 6. Thepressure vessels of FIGS. 4, 5, and 6 are identical to the pressurevessel 40 of FIGS. 1 and 2.

The closure member 142 is slightly different than the closure member 42of FIGS. 1, 2 and 3 in the following respects. A pair of oppositelyextending bayonet lugs 161a and 161b are formed on the exterior ofcylindrical portion 150. Those lugs help to support the filter cartridgein the head member. When the filter cartridge is inserted into the headmember, the cylindrical portion 150 of the closure member with itsattached bayonet lugs must first pass through opening 124 and oppositelydisposed bayonet openings 125a and 125b in the bracket member 112. Aspreviously mentioned the bayonet openings 125a and 125b are of differentsizes, one being narrower than the other. Likewise, the bayonet lugs areof correspondingly different sizes, one being narrower than the other sothat the filter cartridge can be inserted into the head member in onlyone position to assure proper alignment of the inlet and outlet ports inthe head member and closure member. The counterbore 129 in the lower endof the head member 114 is of a predetermined depth--substantially thesame depth as the thickness of the bayonet lugs--and this together withthe bracket member establishes the axial position of the closure member142 in the head member 114.

O-ring seals 62, 64, and 66 disposed on the outer cylindrical surface ofclosure member 142 as shown in FIGS. 4, 5, and 6 occupy the samerelative positions with respect to the inlet and outlet port means asthey do in the embodiments of FIGS. 1 and 2.

After insertion into the head member, the filter cartridge 116 isrotated a quarter turn until the one side of each of the bayonet lugs161a and 161b come to rest against stops 163a and 163b formed in thehead member as shown in FIG. 10. Rotation of the filter cartridge tothis position aligns the fluid inlet and outlet ports in the side wallof the closure member with the inlet and outlet ports in the headmember. The bayonet lugs are secured between the bracket member 112 andthe bottom of counterbore 129. Thus the bayonet lugs are effectivethrough coaction with the stop means to align the fluid port means andare further effective to position the closure member in the head memberagainst axial movement thus preventing the filter cartridge frombecoming dislodged as a result of gravity forces.

In the FIG. 4 embodiment a tubular screen strainer 178 is associatedwith the fluid inlet passage 54, the upper end of the strainer 178 beingattached to the closure member by some appropriate well-known means.

The filter means used in the filter cartridge includes the filter septum143 which may be made of a woven material. It is disposed near thebottom of the pressure vessel and is attached to the outlet passage 52by a tube 180 which in turn is attached to the closure member and formspart of the outlet passage 52. The filter means also may include afilter media 46 which may fill up all of the pressure vessel. The filtermedia preferably is a granular activated carbon. Therefore, wheninfluent enters the inlet 32 and proceeds through inlet passage 54 itmoves through the filter media 46, then through the collector or filterseptum 143, into tube 180 and out through the outlet passage 52 andoutlet port 30.

The insertion and removal of the disposable filter cartridge into andfrom the system is a simple task. Since influent, usually water, issupplied to the system under pressure, a shut-off valve (not shown)usually will be provided in the inlet line somewhere upstream from theinlet port. This valve is shut off during installation or replacement ofa filter cartridge into the system. With the shut-off valve closed thefilter cartridge is inserted into the head member by lining up thebayonet lugs 161a and 161b with the appropriate size bayonet openings125a and 125b. Once properly lined up the filter cartridge is insertedinto the head member until the bayonet lugs contact the shoulder 182 andthen turned a quarter turn until the bayonet lugs contact the stops 163aand 163b. Opening the shut-off valve again place the system inoperation.

The embodiments shown in FIGS. 5 and 6 are substantially the same asthat of FIG. 4, the only difference being the type of filter means used.In FIG. 5, for example, the use of a folded or pleated filter septum 184is illustrated. Powdered filter media 185 also at least partially fillsthe pressure vessel 40. The filter media could be finely powdered carbonand/or other well known powdered filter media. The septum 184 isconnected to and supported on a septum support tube 186 which isconnected to passage 54. The tube 186 thus functions both as a septumsupport and as an outlet tube from the septum 184 to carry filteredfluid form the septum 184 through the inlet 188 in support tube 186 andthen to passage 54. In this embodiment the inlet and outlet passages inthe head member and closure member are reversed from that shown in FIG.4. An inlet tube 190 is connected to passage 52 of the closure memberand extends down through the filter septum 184 to the bottom of thepressure vessel. A check valve 192, which may be of the flapper type, isconnected to the lower end of inlet tube 190. Inlet fluid, therefore,passes downwardly through tube 190, check valve 192 and the powderedfilter media 185, through the filter septum 184, through support tube186 and out through passage 54 and outlet port 32.

In the embodiment of FIG. 6 the filter means is of the same type asshown in FIG. 2. The embodiment of FIG. 6 is essentially the same as theembodiment shown in FIG. 2 but turned upside down thus requiring thebayonet lug supporting means as do the embodiments of FIGS. 4 and 5.Inlet fluid enters at port 32, proceeds through passage 54 down into thepressure vessel, radially inwardly through filter unit 74 as indicatedby the arrows, into passage 76 and out through passage 52 and outletport 30.

While certain preferred embodiments of the invention have beendisclosed, it will be appreciated that these are shown by way of exampleonly, and the invention is not to be limited thereto as other variationswill be apparent to those skilled in the art and the invention is to begiven its fullest interpretation within the terms of the followingclaims.

What is claimed is:
 1. A filter assembly comprising:(a) a bracket memberadapted to be supported on a supporting structure, (b) a head memberattached to said bracket member for receiving a filter cartridgetherein, said head member comprising,a cylindrical cup-like structureformed with an annular bore and having inlet and outlet ports in thecylindrical wall thereof and adapted to have a filter cartridge securedtherein, (c) a filter cartridge including(1) a pressure vessel closed atone end, (2) a closure member sealingly disposed in the open end of saidpressure vessel, said closure member including,(a) an annular baseportion which is fitted onto and secured onto the open end of saidpressure vessel, (b) an elongated cylindrical portion formed integrallywith said base portion and adapted to be inserted into said head memberin sealing engagement therewith, (c) a pair of axially extending inletand outlet passages formed in said elongated cylindrical portion,(1) oneof said passages being formed with a first communicating port in thecylindrical wall of said cylindrical portion, (2) the other of saidpassages being formed with a second communicating port in thecylindrical wall of said cylindrical portion, (3) said first and secondcommunicating ports being in fluid communication with the inlet andoutlet ports of said head member, and (3) filter means disposed withinsaid pressure vessel between the inlet to and outlet from said pressurevessel.
 2. The filter assembly of claim 1 including three O-ring sealdisposed on the cylindrical wall of said closure member in such manneras to separate the inlet port with its associated inlet passage from theoutlet port with its associated outlet passage and further to seal theinternal pressure from the surrounding atmosphere when the closuremember is inserted into said head member.
 3. The filter assembly ofclaim 2 including vent means formed in said head member.
 4. The filterassembly of claim 2 including cooperative alignment means formed on saidhead member and on said closure member for properly aligning the inletand outlet ports in said head member and closure member.
 5. The filterassembly of claim 4 whereinsaid alignment means comprises cooperatingpin and recess means associated with said head member and said closuremember.
 6. The filter assembly of claim 4 whereinsaid alignment meanscomprises a recess in the outer end of said closure member andcooperating pin means associated with said head member.
 7. The filterassembly of claim 6 including vent means formed in said cooperating pinmeans.
 8. The filter assembly of claim 2 whereinsaid head member ispositioned with its open end facing upwardly, whereby the filtercartridge is supported in said head member by gravity.
 9. The filterassembly of claim 1 includingfirst, second, and third O-ring sealsdisposed on the cylindrical wall of said closure member, said first andthird O-ring seals being disposed in such a manner as to seal off theinternal pressure from the surrounding atmosphere in a system in whichthe filter assembly is disposed, said second O-ring seal being disposedbetween said first and third O-ring seals to separate the inlet portwith its associated inlet passage from the outlet port with itsassociated outlet passage.
 10. The filter assembly of claim 1whereinsaid filter means includes a filter septum disposed in saidpressure vessel, said filter septum being connected with the outletpassage in said closure member, and further including a filter mediadisposed in said pressure vessel and surrounding said filter septum. 11.The filter assembly of claim 10 whereinsaid filter media is a finelypowdered material.
 12. The filter assembly of claim 10 whereinsaidfilter media is a mixture of more than one type of powdered materials,at least one of them being powdered activated carbon.
 13. The filterassembly of claim 1 whereinsaid filter means includes a cylindricalfilter cartridge disposed in said pressure vessel, said cartridge beingconnected to the outlet passage in said closure member.
 14. The filterassembly of claim 1 includingannular opening means formed in saidbracket member for receiving said closure member of said filtercartridge therethrough, said opening means being formed with a pair ofoppositely disposed bayonet openings, and a pair of radially estendingbayonet locking lugs formed on the outer surface of said closure memberwhich are adapted to be aligned with said bayonet openings in saidbracket member when said filter cartridge is inserted into or removedfrom said head member, said bayonet lockings lugs in the assembly beingadapted to coact with said bracket member to secure the filter cartridgein the assembly and prevent its being released from the assembly.
 15. Ina filter assembly the combination comprising:(a) a head member adaptedto be disposed in a fluid conduit and adapted to have a filter cartridgeinserted thereinto, said head member comprising a cup-like structurehaving an annular bore formed therein and inlet and outlet ports formedin the wall portion and communicating with said bore, (b) a filtercartridge including(1) a pressure vessel closed at one end, (2) aclosure member sealingly disposed in the open end of said pressurevessel, said closure member including,(a) an annular base portion whichis fitted onto and secured onto the open end of said pressure vessel,(b) an elongated cylindrical portion formed integrally with said baseportion and adapted to be inserted into said head member in sealingengagement therewith, (c) a pair of substantially axially extendinginlet and outlet passages formed in said elongated cylindricalportion,(1) one of said passages being formed with a first communicatingport in the cylindrical wall of said cylindrical portion, (2) the otherof said passages being formed with a second communicating port in thecylindrical wall of said cylindrical portion, (3) said first and secondcommunicating ports being in fluid communication with the inlet andoutlet ports of said head member, (d) cooperative alignment means onsaid head member and said closure member for aligning the inlet andoutlet ports in said head member and corresponding ports in said closuremember, (e) first, second, and third O-ring seals disposed on thecylindrical wall of said closure member, said first and third O-ringseals being disposed in such a manner as to seal off the internalpressure from the surrounding atmosphere in a system in which the filterassembly is disposed, said second O-ring seal being disposed betweensaid first and third O-ring seals to separate the inlet port with itsassociated inlet passage from the outlet port with its associated outletpassage, and (3) filter means disposed within said pressure vesselbetween the inlet to and outlet from said pressure vessel.
 16. Thecombination of claim 15 whereinsaid alignment means comprisescooperating pin and recess means associated with said head member andsaid closure member.
 17. The combination of claim 15 whereinsaidalignment means comprises a recess in the outer end of said closuremember and cooperating pin means associated with said head member. 18.The combination of claim 15 whereinsaid cooperative alignment meansinclude circumferentially spaced stop means formed on said head memberand radially extending lug means formed on said closure member forcoacting with said circumferentially spaced stop means in the filterassembly.
 19. The combination of claim 15 including vent means formed insaid head member.
 20. The combination of claim 15 whereinsaid filtermeans includes a filter media filling a substantial portion of thepressure vessel.
 21. The combination of claim 20 wherein said filtermedia is a granular activated carbon.
 22. The combination of claim 20wherein said filter media is a finely powdered material.
 23. Thecombination of claim 20 whereinsaid filter media is a mixture of morethan one type of powdered materials, at least one of them being powderedactivated carbon.
 24. The combination of claim 15 whereinsaid filtermeans includes a filter septum disposed in said pressure vessel, saidfilter septum being connected with the outlet passage in said closuremember, and further including a filter media disposed in said pressurevessel and surrounding said filter septum.
 25. The combination of claim15 whereinsaid filter means includes a cylindrical filter cartridgedisposed in said pressure vessel said cartridge being connected to theoutlet passage in said closure member. .Iadd.
 26. A filter cartridgecomprising:a pressure vessel closed at one end including filter meansdisposed therein, a closure member sealingly disposed in the open end ofsaid pressure vessel, said closure member including,(a) an annular baseportion which is secured to the open end of said pressure vessel, (b) anelongated cylindrical portion formed integrally with said base portionand adapted to be inserted into a mating head member in sealingengagement therewith, (c) a pair of axially extending inlet and outletpassages formed in said elongated cylindrical portion,(1) one of saidpassages being formed with a first communicating port in the cylindricalwall of said cylindrical portion, (2) the other of said passages beingformed with a second communicating port in the cylindrical wall of saidcylindrical portion, (3) said first and second communicating ports beingadapted to establish communication with inlet and outlet ports of a headmember with which said closure member is adapted to be associated, (d)first, second and third seal members disposed on the cylindrical wall ofsaid closure member, said first of said seal members being axiallyspaced from and disposed between said first and second communicatingports, and said second and third of said seal members being axiallyspaced from and on opposite sides of said first seal member for sealingthe internal pressure from the surrounding atmosphere when the closuremember is inserted into a head member with which the closure member isadapted to be associated..Iaddend. .Iadd.
 27. The filter cartridge ofclaim 26 wherein said first, second and third seal members are O-ringseals..Iaddend. .Iadd.28. The filter cartridge of claim 26 includingradially extending projection means disposed on the outer periphery ofsaid cartridge for securing the cartridge in a filter assembly of whichit is adapted to be a part. .Iaddend. .Iadd.29. The filter cartridge ofclaim 26 including a pair of radially extending bayonet locking lugsformed on the outer surface of said closure member for securing thefilter cartridge in a filter assembly of which it is adapted to be apart..Iaddend. .Iadd.30. The filter cartridge of claim 29 wherein saidbayonet lugs are of a different size and thereby are effective tocontrol the proper positioning of the cartridge in a head with which thecartridge is adapted to be associated..Iaddend. .Iadd.31. The filtercartridge of claim 26 including alignment means on said closure memberadapted to cooperate with alignment means on a head member with whichthe filter cartridge is adapted to be associated for aligning inlet andoutlet ports in the closure member and corresponding ports in the headmember..Iaddend. .Iadd.32. The filter cartridge of claim 26 includingfilter means disposed within said pressure vessel between the inlet toand outlet from said pressure vessel, said filter means including(a) afilter septum disposed in the pressure vessel, said filter septum beingconnected with the outlet passage in said closure member, and (b) filtermedia disposed in said pressure vessel and surrounding said filterseptum..Iaddend. .Iadd.33. The filter cartridge of claim 32 wherein saidfilter media is a granulated activated carbon..Iaddend. .Iadd.34. Thefilter cartridge of claim 32 wherein said filter media is a finelypowdered material..Iaddend. .Iadd.35. The filter cartridge of claim 32wherein said filter media is a mixture of more than one type of powderedmaterials, at least one of them being powdered activatedcarbon..Iaddend. .Iadd.36. A filter cartridge comprising:a pressurevessel closed at one end including filter means disposed therein; aclosure member sealingly disposed in the open end of said pressurevessel, said closure member including,(a) an annular base portion whichis secured to the open end of said pressure vessel, (b) an elongatedcylindrical portion formed integrally with said base portion and adaptedto be inserted into a mating head member in sealing engagementtherewith, (c) a pair of axially extending inlet and outlet passagesformed in said elongated cylindrical portion,(1) one of said passagesbeing formed with a first communicating port in the cylindrical wall ofsaid cylindrical portion, (2) the other of said passages being formedwith a second communicating port in the cylindrical wall of saidcylindrical portion, (3) said first and second communicating ports beingadapted to establish communication with inlet and outlet ports of a headmember with which said closure member is adapted to be associated, (d)first, second and third seal members disposed on the cylindrical wall ofsaid closure member, said seal members being so constructed and arrangedin relation to the associated first and second communicating portsformed in said cylindrical portion that oppositely exerted axialpressures tend to negate each other to thereby effectively minimize thenet axial pressure on the cartridge so that the axial pressure will noturge the filter cartridge out of a head with which the cartridge isadapted to be associated. .Iaddend.